Effects of fermentation temperature on the amino acid composition of moromi mash during fermentation were studied on laboratory scale sake brewing carried out using Kyokai No.7 yeast. As the result, it was possible to make distinctions among various fermenting processes by controlling temperature patterns during moromi mash fermentation. In the moromi fermented at low temperature (Max. Temp. 10-12°C), concentrations of lysine and methionine were lower than those in the mash fermented at high temperature (Max. Temp. 14-20°C). But these phenomena were not observed in the fermentation of koji extract media. In the moromi mash fermented at low temperature, the concentration of cystine in yeast cells was higher than that fermented at high temperature. It was suggested that temperature is concerned with the uptake of amino acids by yeasts in parallel fermentation. The uptake of sulfur-containing amino acids were characteristic in the mash fermented in low temperature, and the fact was suggested to result in the appearance of hydrogen sulfide in the early stage of moromi mash fermentation.